High voltage magnetic arc extinguishing means



Aug. 14, 1956 J. D. WOOD 2,759,073

HIGH VOLTAGE MAGNETIC ARC 'EXTINGUISHING MEANS Filed Nov. 22, 1952 3Sheets-Sheet 1 4 INVENTOR P1 i JOSEPH J. 01002 7 J BY 410W 0 ATTORNEY J.D. WOOD Aug. 14, 1956 HIGH VOLTAGE MAGNETIC ARC EXTINGUISHING MEANSFiled Nov. 22, 1952 5 Sheets-Sheet 5 JIE 5A- 1 M y. w M 0 w m up IIJ l II I 1 I I 1 I I I l 1 l I I I l I I I I I I I I I I l l I I l l I IIIHNZ I I I 1 r 1 I 1 [.Jllll|ll|||||:|l|:|l||||1||||||E N r m w 1 a w Jw Q 0 Y B M a w, a J w w a h A 4 W 4 w a 111i; llllllllllllllllllllllllllllllllll l a m 0 m, M. n w J a f M w m M v 1 34 A 4 7 M l m United States Patent HIGH VOLTAGE MAGNETIC ARCEXTINGUISHIN G MEANS Joseph D. Wood, Wayne, Pa., assignor to I-T-ECircuit Breaker Company, Philadelphia, Pa., a corporation ofPennsylvania Application November 22, 1952, Serial No. 322,027

7 Claims. (Cl. 200147) breaker in which my novel are chute is to bemounted and with which my novel are chute is to cooperate is a highvoltage high capacity air break unit so arranged as to lend itself tomass production techniques by the utilization of individual relativelyinexpensive sub-assemblies.

In a high voltage high capacity breaker the first and most importantstep involved is the construction of the arc chute and of the arcblow-out mechanism so that any are which is drawn between the contactsas they open may be readily extinguished before damage to the breaker orto the circuit may occur.

My novel circuit breaker includes a simple unitary arc chute structuremade as a single unit provided with a disconnect and so arranged that itmay readily be mounted on the circuit breaker and connected thereto orremoved therefrom as a whole without the necessity for special tools.

My novel are chute thus combines the essential ideas of simplifiedconstruction for greater economy and simplitied arrangement in the formof a single unit assembly which may readily be mounted on any circuitbreaker of the class to which the arc chute is to be applied. The arechute may readily be removed for inspection of the contacts of thecircuit breaker or for replacement or repair of any part that mayrequire such replacement or repair.

My novel are chute is supported and carried entirely by my novelblow-out mechanism which in turn is secured to the main panel of thecircuit breaker in a readily movable manner hereinafter described. Theblowout mechanism thus constitutes a unit sub-assembly by itself.

The blow-out mechanism comprises essentially a U- shaped iron structure,the base of which is surrounded by the blow-out coil and the legs ofwhich extend out perpendicularly to the panel on which the circuitbreaker is mounted. These legs of the U-shaped iron structure carry thearc chute; and the arc chute may he slid on to or off these legs forplacement or removal.

As above pointed out, the blow-out iron circuit is made up of a corearound which the blow-out coil is wound; to the ends of the core areattached the side plates which project forward nearly the entire depthof the arc chute. These plates also act as slides or runners andsupports for the arc chute and the complete assembly is thus supporteddirectly on the back panel support.

Heretofore in the construction of blow-out mechanisms, it has been foundthat a concentration of flux at the coil end occurs with solid sideplates so that only the coil end of the arc chute is used.

In addition, and in order to enhance the blow-out effect, auxiliaryblow-out iron plates are attached to the runner strip on each side ofthe arc chute and divert part of the main blow-out field down into thevicinity of the contact.

By this novel construction the blow-out structure and the arc chutestructure are mechanically separated and independent of each other sothat the arc chute is much lighter and easier to remove for inspectionand so that the blow-out construction acts as a support for the arcchute.

The blow-out mechanism is so arranged that it may move an are at lowinterrupting current as well as an are at high interrupting currentproperly into the arc chute so that the same may be extinguished-thesaid blowout mechanism operating for this purpose over the entire rangeof interrupting capacity of the circuit breaker Without the necessityfor additional aid or other expedients. This we achieve in part bypassing only a portion of the arcing current through the blow-out coils,the percentage of such current decreasing as the fault currentincreases.

An important and primary object of my present invention is the provisionin the structure and organization above described of a novel areextinguishing plate, said plate being of insulating material andarranged to extend transversely of the path of the are. A plurality ofsuch plates are used in order to make up a parallel spaced plate arechute. These plates are arranged vertically in an arc chute wherein thearc is drawn by substantial horizontal movement of the movable contact.

Each of the plates is provided with a vertical notch communicating withthe lower part of the plate, the notch be ing arranged to one side ofthe vertical center line of the plate. By reversing successive plateswith respect to each other the successive notches are arranged to forcethe are drawn through the plates into a sinusoidal path, therebylengthening the arc. Since the notches do not extend to the top of theplates the blow-out action, when the arc is driven toward the top of thearc chute, also produces a sinusoidal effect in a vertical plane.

The combination of the sinusoidal effect in the horizontal plane duringthe initial arc extinguishing action with the addition of the sinusoidaleffect imposed on the arc in a vertical plane toward the top of the arcchute produces an effect of lengthening and cooling of the are, which results in rapid and efiicient extinguishment thereof.

The plates themselves are preferably made of a glass bonded micacomposition which is for all practical purposes completely inert Withoutemitting any gases or other material which may interfere with therequired dielectric properties of the arc chute. The plates, of course,may be made of any suitable material which is sufficiently inert and ofa sufiiciently high dielectric to withstand the arc currents andtemperatures.

The vertical notch is preferably a compound notch having a relativelywide bottom opening tapering at a relatively large angle to a smalleropening, thereby providing free access or entry of the are into theplates.

Thereafter the notch tapers for a substantially greater distance at asmaller angle, providing for a gradual squeezing of the arc and the arcgases generated thereby. This second section of the notch thencommunicates with a relatively very narrow notch with substantiallyparallel sides which tends to squeeze the are still further.

My invention further contemplates that the are extinguishing plates havemarginal flanges, preferably integral therewith, and serving asappropriate spacing elements for the arc extinguishing plates.

The foregoing and many other objects of my invention 3 will becomeapparent from the following description of the drawings in which:

Figure 1 is a side, back view in perspective, showing the type ofcircuit breaker which could use my novel are chute.

Figure 2 is side view of the arc chute assembly.

Figure 3 is a front view of the arc chute assembly.

Figure 4a is a top view of the arc chute assembly of Figure 3 havingU-cross-section arc plates.

Figure 4b is a top view of the arc chute assembly of Figure 3 similar toFigure 4a but having I-cross-section arc plates.

Figure 5a shows a cross sectional view of an arc plate constructed inaccordance with my invention.

Figure 5b shows a front view of the arc plate of Figure 5a.

Figure 5c shows a side view of the arc plates of Figures 5a and 512.

Figure 6a shows a cross-sectional view of an arc plate having adifferent embodiment from that of Figure 5a and constructed inaccordance with my invention.

Figure 6b shows a front view of the arc plate of Figure 6a.

Figure 6c shows a side view of the arc plate of Figures 6a and 6b.

Figure 1 shows a high speed, high capacity circuit breaker which couldutilize the arc plates of my invention. A detailed description of theconstruction and operation of the circuit breaker of Figure 1 is givenin copending application Serial No. 746,554 filed May 7, 1947, nowPatent No. 2,646,481, dated July 21, 1953.

In general, a supporting structure comprising support members 10, 11,12, 13, 14, I15, 20, 21, 23 and 24 support sub-assemblies such as thecontrol panel assembly 47, trip unit assembly 43 and the operatingmechanism assembly 46.

As specifically described in the above mentioned application, contactoperating arms 52 project up from the operating mechanism assembly 46are so constructed as to cause contact engagement to electricallyconnect the electric terminals 30 and 31.

The contacts are positioned within the housing formed by the plates 56and 63 as are the blow out assembly and the arc chute assembly to whichmy invention is directed.

Arc chute The blow-out assembly serves as support for the arc chutedescribed in Figures 2, 3, 4a and 4b. The are chute assembly mountedabove the contact assembly provides for a positive and efficient arcinterruption. it consists of insulation side walls 12,2 5, front andback are runners 291 and 290 respectively and a series of arcextinguishing plates 26%: mounted in spaced relation transverse of thearc path and a strong magnetic bl iv-out field to force the are into theare chute.

The sides 257 (Figures 2, 4a and 412) have fastened at their lowerportion, adjacent the arcing area, inner arc resisting insulating plates26 269 of special composition hereinafter described. The arc resistingplates 269 are chamfered along their upper edges at Z62262 to provide astraight lockin edge for the cross plates 260 and the spacers 261. Thelower ends of the cross plates 26% and the spacers 261 are appropriatelyshaped to fit the chamfered edge 262.

As the arc is driven into the chute by the magnetic field, it passesrapidly through the are extinguishing plates 269.

These plates as shown particularly in Figures 5a, 5b, 50, 6a, 6b and 60have a main transverse body 360 and vertical flange members 2-61, 261which serve, as shown in Figure 4a, to space the plates appropriatelyfrom each other. The upper edge 301 of each of the plates issubstantially straight and the lower edge 3th. of each of the plates isprovided with an otf-centcr vertical notch arrangement 363. The verticalnotch arrangement 303 has a wide opening 304 at the lower end taperingrapidly, as defined by the angle of the edges 3%, 36, to a relativelynarrow opening 307. Thereafter, the edge 3% of the notch issubstantially vertical while the edge 389 of the notch ta ers at asubstantially small angle to the vertical edge 310 where the notch edgesare relatively very close together.

Thereafter, the two edges 308a and 312 defining the notch are parallel.

By way of example and in order to indicate the relative proportions, inan arc extinguishing plate having a height of 16%; inches, the width ofthe opening at 364 would be 1% inches and the opening to the narrowernotch at 307 would be 1.5 inches from the bottom of the plate. Theopening at 310 to the still narrower parallel side of the notch would be6.25 inches from the bottom of the plate and the distance from thebottom of the plate to the end 313 of the notch would be 8.25 inches.

The foregoing figures are given not as necessarily critical values, butprimarily to indicate the relative proportions of the three parts of thesingle notch in the plate.

it will be seen that by making the initial opening 304 substantiallycentral of the plate easy access of the are into the stack of plates isprovided. Thereafter, since the slope 306 is greater than the slope 305,the notch is shifted to one side of the plate (toward the right withrespect to Figure 5b).

Thereafter, by making the edge of the notch 333-3ii8a vertical andcontinuous the slope 309 causes a further shift of the notch toward theright of the plate. Consequently, the notch is displaced toward one sideof the plate and a reversal of successive plates produces a sinusoidalarrangement of the notch openings since the notch openings, particularlyat the area of the notch defined by side wall 308, are displacedlaterally with respect to each other in successive plates.

As the arc passes the cross-over point of the plates it is forced into aZig-zag or sinuous path gradually but rapidly increasing its length andbringing it into contact with the larger and larger cool surfaces of theplates. The are must thus bend around the edges of the plates which areeffective in circuit interruption. The positive and efficient arcinterruption is affected by the cooling,

' lengthening and squeezing of the are at numerous points all along itspath.

In addition to this kind of lengthening of the arc, the arc is, ofcourse, further lengthened in a vertical plane by the sinusoidalsqueezing thereof which occurs owing to the blow-out action moving thearea of the are above the top 313 of the notch in the plate. While theplates preferably are used with integral flanges 26 forming the spacesbetween them these provide the most efiicient are resistant spacingmethod. It will be obvious, of course, that the plates may also bemounted in the manner described in my aforementioned application, wherethey may be supported in matching grooves in opposite sides of the sidewalls in the arc extinguishing structure. By means of the flanges 261,however, full support of the plates with respect to each other overtheir full length is pro vided and no part of the plate is loose orunsupported.

Figure 6a is an elevation of an l-cross-section are extinguishing platesimilar to that shown in Figure 5a. A cross-sectional view of thisI-cross-section arc plate when assembled in the are is shown in Figure4b.

The plate 300 is preferably made of glass bonded mica composition whichfor all practical purposes is completely inert without emitting anygasses or other material which might interfere with the dielectricproperties of the arc chute.

The plates 300 of Figures 6a, 6b and 6c may be thus of the same suitablematerial used for the plates of Figures 5a, 5b and so that it issufficiently inert and of sufficient dielectric to withstand the arctemperatures.

The modified arc plate of Figures 6a, 6b and 6c differs antidote fromthat shown in Figures a, 5b and Sc by'providing an I-cross-section. Thatis, the integral flange 400-402 and the flange 401-403 extend on bothsides of the base part of the plate 300.

As heretofore mentioned in connection with Figure 5a, theU-cross-section plates require that a right and left hand plate bemanufactured for assembly in the arc chute. However, with the novelmodification, as shown in Figures 6a, 6b and 60, wherein the flangesextend on both sides of the base 300, the so-called right and left handplates are of identical construction, hence greatly facilitatingmanufacturing and production thereof.

It will be noted that all portions of the flange serve as spacers forthe arc plate 300 in substantially the same manner as set forth inconnection with are plates shown in Figures 4a, 5a, 5b and 50.

In the foregoing I have described my invention solely in connection withspecific illustrative embodiments thereof. Since many variations andmodifications of my invention will now be obvious to those skilled inthe art, I prefer to be bound not by the specific disclosures hereincontained but only by the appended claims.

I claim:

1. In a high voltage circuit breaker comprising a main pair ofcooperable contacts and an auxiliary pair of cooperating contacts; arcextinguishing means positioned above said cooperating contacts andcomprising a magnetic yoke, a blow-out coil and a plurality of insulatorplates; said magnetic yoke comprising a U-shaped member energized bysaid blow-out coil, said blow-out coil energized by the separation ofsaid cooperating contacts, each of said plurality of insulator plateshaving a large center opening at the lower end thereof cooperating withan intermediate center slot which in turn cooperates with a verticalcenter slot, said large center opening being substantially symmetricalwith respect to the vertical center line of said insulator plate, saidintermediate center slot and said vertical center slot being positionedto one side of said vertical center line of said insulator plate.

2. In a high voltage circuit breaker comprising a main pair ofcooperable contacts and an auxiliary pair of cooperating contacts; arcextinguishing means positioned above said cooperating contacts andcomprisng a magnetic yoke, a blow-out coil and a plurality of insulatorplates; said magnetic yoke comprising a U-shaped member energized bysaid blow-out coil, said blow-out coil energized by the separating ofsaid cooperating contacts, said plurality of plates positioned in spacedparallel relation to each other and with said magnetic yoke, saidinsulator plates being made from a non-gas emitting material and havinga first, second and third center slot located therein; said first centerslot positioned at the bottom of said plate substantially symmetricalwith respect to the vertical center line thereof, said second centerslot progressively decreasing in width from a first end to a second endof said slot, said first end of said second center slot cooperating withsaid first center slot, said second end of said second center slotcooperating with said third center slot, said third center slot being ofuniform width throughout and positioned on one side of the verticalcenter line of said plates, alternate plates of said are extinguishingmeans having said third slot positioned on the same side of saidvertical center line, adjacent plates having said third slot positionedon opposite sides of said vertical center line.

3. A plurality of insulator plates for an arc extinguisher made from anon-gas emitting material and positioned in spaced parallel relation,each of said plates having a first, second and third center slot locatedtherein; said first center slot positioned at the bottom of said platesubstantially symmetrical with respect to the vertical center linethereof, said second center slot progressively decreasing in width froma first end to a second end of said slot, said first end of said secondcenter slot cooperating with said first center slot, said second end ofsaid second center slot cooperating with said third center slot, saidthird center 'slot being of uniform width throughout and positioned onone side of the vertical center line of said plates, alternate plates ofsaid are extinguishing means having said third slot positioned on the.same side of said vertical center line, adjacent plates having saidthird slot positioned on opposite sides of said vertical center line.

4. An arc plate for an arc extinguishing device made from an insulatingmaterial of glass bonded mica which is non-gas emitting and having apair of integral flanges, said integral flanges extending on one side ofsaid plates from the edge adjacent the ends thereof, said plates havinga center slot having a first, second and third section; said first andsecond sections progressively decreasing in width from the bottom to thetop of said are plate, said first section decreasing in width at agreater rate than said second section, said third section having auniform width throughout, said first section positioned substantiallysymmetrical on either side of the vertical center line of said plate,and said second center section positioned in a non-symmetrical mannerwith respect to said vertical center line and said third sectionpositioned on one side of said vertical center line of said plate.

5. A circuit breaker comprising a movable contact arm, a contact engagedthereby in the closed position of the arm, an arc chute, a horn elementfor carrying the are positioned above said engaged contact at one Wallof the arc chute and electrically connected with said engaged contact, asecond horn element for carrying the arc electrically disconnected fromsaid first named element and from said contact arm and positioned at theopposite wall of the arc chute, said are chute comprising a plurality ofinsulator plates for an arc extinguisher made from a non-gas emittingmaterial and positioned in spaced parallel relation, each of said plateshaving a first, second and third center slot located therein; said firstcenter slot positioned at the bottom of said plate substantiallysymmetrical With respect to the vertical center line thereof, saidsecond center slot progressively decreasing in Width from a first end toa second end of said slot, said first end of said second center slotcooperating with said first center slot, said second end of said secondcenter slot cooperating with said third center slot, said third centerslot being of uniform width throughout and positioned on one side of thevertical center line of said plates, alternate plates of said areextinguishing means having said third slot positioned on the same sideof said ver tical center line, adjacent plates having said third slotpositioned on opposite sides of said vertical center line.

6. An arc plate for an arc extinguishing device made from an insulatingmaterial of glass bonded mica which is non-gas emitting and having apair of integral flanges, said integral flanges extending on both sidesof said plates from the edge adjacent the ends thereof, said plateshaving a center slot having a first, second and third section; saidfirst and second sections progressively decreasing in width from thebottom to the top of said are plate, said first section decreasing inwidth at a greater rate than said second section, said third sectionhaving a uniform width throughout, said first section positionedsubstantially symmetrical on either side of the vertical center line or"said plate, and said second center section positioned in anon-symmetrical manner with respect to said vertical center line andsaid third section positioned on one side of said vertical center lineof said plate.

7. A plurality of insulator plates for an arc extinguishing device, eachof said plurality of insulator plates made from an insulating materialof glass bonded mica which is non-gas emitting and having a pair ofintegral flanges; said integral flanges being constructed to positionsaid plurality of insulator plates in spaced parallel relation; saidplates having a center slot having a first, second and third section;said first and second sections progressively decreasing in width fromthe bottom to the top of said arc plates, said first section decreasingin width at a greater rate than said second section, said third sectionhaving a uniform Width throughout, said first section positionedsubstantially symmetrical on either side of the vertical center line ofsaid plate, and said second center section positioned in anon-symmetrical manner with respect to said vertical center line andsaid third section positioned on one side of said vertical center lineof said plate.

1,923,748 Roman Aug. 22, 1933 8 Graves, Jr. June 3, Nan Mar. 17,Dickinson et al. May 25, Zajic Sept. 18,

FOREIGN PATENTS Sweden Apr. 29, Great Britain Sept. 8,

